Rectangular parallelepiped fluid storage and dispensing vessel

ABSTRACT

A fluid storage and dispensing apparatus including a fluid storage and dispensing vessel having a rectangular parallelepiped shape, and an integrated gas cabinet assembly including such fluid storage and dispensing apparatus and/or a point-of-use ventilation gas scrubber in the vented gas cabinet. By the use of physical adsorbent and chemical sorbent media, the gas cabinet can be enhanced in safety of operation, e.g., where the process gas supplied from the gas cabinet is of a toxic or otherwise hazardous character.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation under 35 USC 120 of U.S. patent application Ser.No. 13/966,091 filed Aug. 13, 2013 in the names of Dennis Brestovansky,et al. for “RECTANGULAR PARALLELEPIPED FLUID STORAGE AND DISPENSINGVESSEL,” which in turn is a divisional under 35 USC 120 of U.S. patentapplication Ser. No. 13/168,987 filed Jun. 26, 2011 in the names ofDennis Brestovansky, et al. for “RECTANGULAR PARALLELEPIPED FLUIDSTORAGE AND DISPENSING VESSEL,” and issued Aug. 13, 2013 as U.S. Pat.No. 8,506,689, which in turn is a continuation under 35 USC 120 of U.S.patent application Ser. No. 12/401,325 filed on Mar. 10, 2009 in thenames of Dennis Brestovansky, et al. for “RECTANGULAR PARALLELEPIPEDFLUID STORAGE AND DISPENSING VESSEL,” and issued on Jul. 5, 2011 as U.S.Pat. No. 7,972,421, which is a continuation under 35 USC 120 of U.S.patent application Ser. No. 11/227,944 filed Sep. 15, 2005 in the namesof Dennis Brestovansky, et al. for “RECTANGULAR PARALLELEPIPED FLUIDSTORAGE AND DISPENSING VESSEL,” and issued on Mar. 10, 2009 as U.S. Pat.No. 7,501,010, which in turn is a continuation under 35 USC 120 of U.S.patent application Ser. No. 10/314,777 filed Dec. 9, 2002 in the namesof Dennis Brestovansky, et al. for “RECTANGULAR PARALLELEPIPED FLUIDSTORAGE AND DISPENSING VESSEL,” and issued on Jan. 31, 2006 as U.S. Pat.No. 6,991,671. The priorities of said U.S. patent application Ser. No.13/966,091, U.S. patent application Ser. No. 13/168,987, U.S. patentapplication Ser. No. 12/401,325, U.S. patent application Ser. No.11/227,944 and U.S. patent application Ser. No. 10/314,777 are herebyclaimed under 35 USC 120.

FIELD OF THE INVENTION

The present invention relates generally to a fluid storage anddispensing apparatus including a fluid storage and dispensing vesselhaving a rectangular parallelepiped shape, and to an integrated gascabinet assembly including such fluid storage and dispensing apparatus.

DESCRIPTION OF THE RELATED ART

Sorbent-based fluid storage and dispensing apparatus have come into usein semiconductor manufacturing applications in recent years, as gassupplies for a variety of semiconductor manufacturing unit operations.

Examples of such semiconductor manufacturing operations include, withoutlimitation: ion implantation, using gaseous reagents such as borontrifluoride, arsine, phosphine, and diborane; chemical vapor depositionof metal-containing films, using a wide variety of organometallicprecursor reagent gases; and fabrication of silicon-on-insulator (SOI)optoelectronic device structures, utilizing silicon source reagents suchas silane and halosilane gases.

Commercially available sorbent-based fluid storage and dispensingapparatus include the gas source systems available under the trademarksSDS® and SAGE® from ATMI, Inc. (Danbury, Conn.) and Matheson GasProducts, Inc. (Parsippany, N.J.). Such systems typically include aconventional high-pressure gas cylinder vessel as the receptacle for asolid-phase physical adsorbent medium, e.g., a molecular sieve(aluminosilicate), activated carbon or other material having sorptiveaffinity for the fluid to be stored in and selectively dispensed fromthe gas cylinder vessel. The gas cylinder vessel holds the sorbentmedium in the form of a bed of the sorbent particles, and the vessel ischarged with the sorbate gas so that it is sorptively retained on thesorbent bed at pressures that are typically much lower than the highpressures at which such gas cylinders have historically been used (e.g.,pressures on the order of 1500-5000 torr or even higher) for gasstorage.

The prior art high pressure gas cylinders utilized substantialsuperatmospheric pressures for gas storage, since such pressure levelspermitted significant inventory of gas to be supplied from the vessel.This substantial gas supply capacity, however, is accompanied by thehazards and safety concerns incident to the storage of high pressurecompressed gases. High pressure gas cylinders in the event of cylinderrupture or leakage of gas from a malfunctioning or damaged valve headinvolve the risk of catastrophic release of gas to the ambientatmosphere, as the pressurized gas is rapidly discharged to theenvironment of the vessel. This is particularly problematic inapplications such as semiconductor manufacturing, where many commonlyused reagent and cleaning gases are highly toxic, as well asenvironmentally dangerous, e.g., pyrophoric or explosive, in contactwith the atmosphere.

The physical adsorbent-based gas storage and dispensing vessels of theabove-referenced type achieve a substantial improvement in the safetyand utility of gas supply systems, since the gas is advantageously heldon the sorbent bed at low storage pressures, e.g., subatmosphericpressures of 400 to 700 torr, or otherwise at pressures that are wellbelow those at which gas has been stored in high pressure compressed gascylinders. Accordingly, in the event of a vessel breakage or valve headfailure, the rate of gas egress into the ambient environment is verylow, e.g., diffusional egress when the contained gas on the sorbent bedin the vessel is held at subatmospheric pressure. As a result of itsenhanced safety character, the sorbent-based gas storage and dispensingvessel is correspondingly accommodated by simpler and less costlycontainment, monitoring and back-up safety systems during transportationand use, than those required by conventional high pressure compressedgas cylinders.

In use of the physical adsorbent-based gas storage and dispensingsystem, dispensing is carried out by effecting desorption of gas fromthe physical adsorbent medium held in the interior volume of the vessel,so that the desorbed gas may then be flowed out of the vessel.

Desorption can be effected by a pressure differential, whereby apressure is provided exteriorly of the vessel that is lower than theinterior pressure in the vessel. Alternatively, or additionally,desorption may be effected by heating of the physical adsorbent mediumso as to disrupt the low associative bonds between the sorbate gas andthe physical adsorbent medium. As a still further dispensing modality, acarrier gas may be flowed through the interior volume of the gascylinder vessel, so as to impose a concentration differential on theadsorbed gas to effect mass transfer of the sorbate gas into the carriergas stream, for subsequent dispensing from the vessel with thethrough-flowing carrier gas.

The gas cylinder vessel, as used for conventional high-pressurecompressed gas storage and dispensing, and as heretofore used forphysical adsorbent-based gas storage and dispensing systems, is, asdenoted by its name, a cylindrically-shaped vessel, typically formed ofsteel or other metal alloy, which has an upper neck opening. A valvehead assembly is coupled to the neck opening, e.g., by welding, brazing,or the like, and includes a flow control valve in a valve head blockcontaining a flow passage, with the active valve element being disposedin the flow passage and selectively openable and closable, as desired,to enable discharge flow of the reagent fluid from the interior volumeof the gas cylinder vessel.

The valve head may include a hand wheel, automatic valve acutator orother structural elements for operation of the valve. The valve headtypically is fabricated with a flow connector at a discharge facethereof, or equipped with other means for coupling flow lines, conduits,manifolds, etc. to the valve head, to enable gas to be flowed from thevessel through the valve head and flow circuitry coupled thereto, to alocus of use. The valve head may optionally include additional passagesand ports therein, e.g., for fill of the vessel with sorbent medium, forcharging of the installed sorbent bed with adsorbable gas, for purgingof the vessel, for bake-out of the sorbent medium in the vessel inpretreatment thereof, etc., and the valve head may be integrated with orcoupled to suitable dispensing, monitoring, instrumentation and controldevices, as desired for operation of the gas storage and dispensingsystem.

Fluid storage and dispensing apparatus of the above-described type aremore fully described in U.S. Pat. No. 5,518,528 issued to Glenn M. Tomand James V. McManus, the disclosure of which is hereby incorporatedherein by reference in its entirety.

The vessels that have been employed in the commercial physicaladsorbent-based low pressure gas storage and dispensing systems havecontinued to be the heavy metal cylinders of the type conventionallyused in high-pressure compressed gas storage and dispensing apparatus.This persistence of usage of the heavy metal cylinders in sorbent-basedsystems is attributable to a number of factors.

Such cylindrical vessels have been in use for over 100 years, and aregenerally approved by regulatory authorities worldwide for storage,transport and dispensing of gases. These vessels are readily available,being mass-produced by a number of manufacturers. They are relativelyinexpensive, and widely accepted.

Ancillary to these factors is the fact that since volume of stored gasis a function of pressure, cylindrical vessels as a result of theirminimum area (i.e., circular) cross-sectional shape, are able toaccommodate elevated pressure levels of contained gas, with minimumstress and deformation, relative to other geometries. It has thereforebeen common practice to utilize such vessels at the highest pressureconsistent with safety considerations, in order to maximize theinventory of gas in the vessel. Since the cylindrical vessels are thus“overdesigned” for high pressure gas duty, such vessels have beenregarded as a safe packaging. Further, where toxic and hazardous gasesare involved, regulations have mandated such safe packaging.

For all these reasons, heavy metal cylindrical vessels have been thestandard packaging for physical adsorbent-based gas storage and deliverysystems. Despite this fact, it is to be recognized that such vesselshave numerous associated deficiencies. As a consequence of theiroverdesigned character, the cylinder wall is thick, and due to theirfabrication of steel or other structural metals, such vessels havesignificant weight and therefore are costly to transport, relative tolighter weight articles. Further, the heavy cylindrical vessels are ofvertically upstanding elongate form, having a length to diameter ratiothat is generally >>1, and thus are bulky and unwieldy to move, installand change out.

There is therefore a compelling need in the art for new and improvedpackaging for physical adsorbent-based gas storage and dispensingsystems.

SUMMARY OF THE INVENTION

In one aspect, the invention relates to a fluid storage and dispensingapparatus, comprising a fluid storage and dispensing vessel having aninterior volume, wherein the interior volume contains a physicaladsorbent sorptively retaining a fluid thereon and from which the fluidis desorbable for dispensing from the vessel, and a dispensing assemblycoupled to the vessel for dispensing desorbed fluid from the vessel,wherein the fluid storage and dispensing vessel is of rectangularparallelepiped form.

Another aspect of the invention relates to a gas cabinet assembly,comprising:

a gas cabinet defining an enclosed interior volume and including flowcircuitry in said interior volume arranged for dispensing of gas fromthe cabinet; and

a gas source disposed in the interior volume of the gas cabinet andcoupled in gas supply relationship to the flow circuitry, wherein saidgas source comprises at least one fluid storage and dispensing vessel ofrectangular parallelepiped form, each said fluid storage and dispensingvessel containing a physical adsorbent sorptively retaining said gasthereon, and a dispensing assembly coupled to said fluid storage anddispensing vessel for dispensing said gas from the vessel for flow tosaid flow circuitry.

A further aspect of the invention relates to a method of reducingfootprint of a gas cabinet assembly comprising a gas cabinet containinga gas source including at least one gas storage and dispensing vesselcontaining a physical adsorbent sorptively retaining said gas thereon,said method comprising providing each of said at least one gas storageand dispensing vessel as a vessel with a rectangular parallelepipedform.

A still further aspect of the invention relates to a method of storingand dispensing a gas at low pressure, comprising: fabricating a vesselhaving a rectangular parallelepiped form; disposing a physical adsorbentin the vessel having sorptive affinity for said gas; charging said gasto said vessel for adsorption on said physical adsorbent; sealing saidvessel with a valve head containing an actuatable valve, to enclose thephysical adsorbent and adsorbed gas, and isolate same from an exteriorenvironment of the vessel; desorbing the adsorbed gas from the physicaladsorbent, and actuating the actuatable valve in the valve head, to flowgas from the vessel and through the actuatable valve, for gasdispensing.

In another aspect, the invention relates to a method of reducing fluidburden on an exhaust scrubber of a semiconductor manufacturing facilitycomprising a vented gas cabinet through which ventilation gas is flowedin operation of the gas cabinet, said method comprising contacting saidventilation gas prior to discharge thereof from the gas cabinet with ascrubbing medium in the gas cabinet, to remove scrubbable contaminanttherefrom, and discharging scrubbed ventilation gas from the gascabinet, whereby need for treatment of discharged ventilation gas bysaid exhaust scrubber of the semiconductor manufacturing facility isobviated.

Yet another aspect of the invention relates to a gas cabinet assemblycomprising: a vented gas cabinet defining an enclosed interior volumeand including flow circuitry in said interior volume arranged fordispensing of process gas from the cabinet; a process gas sourcedisposed in the interior volume of the gas cabinet and coupled in gassupply relationship to the flow circuitry; a ventilation gas sourcearranged for feeding ventilation gas to the vented gas cabinet; aventilation gas outlet for discharging ventilation gas from the ventedgas cabinet; and a point-of-use scrubber disposed in the interior volumeof the vented gas cabinet, arranged to remove scrubbable contaminantfrom the ventilation gas prior to discharge of the ventilation gas fromthe vented gas cabinet via the ventilation gas outlet.

Other aspects, features and embodiments of the present invention will bemore fully apparent from the ensuing disclosure and appended claims.

SUMMARY OF THE INVENTION

FIG. 1 is a perspective view of a rectangular parallelepiped fluidstorage and dispensing vessel according to one embodiment of the presentinvention, with a pipe valve connection.

FIG. 2 is a perspective view of a rectangular parallelepiped fluidstorage and dispensing vessel according to another embodiment of thepresent invention, with a flange type valve connection.

FIG. 3A is a front cross-sectional view of a portion of a rectangularparallelepiped fluid storage and dispensing vessel of the type shown inFIG. 2, the vessel including a adsorbent material wherein but lacking alid. FIG. 3B provides the same view as FIG. 3A, with the vessel beingclosed with a lid having an associated valve assembly including aportion extending downward from the lid.

FIG. 4 is a schematic representation of a gas cabinet assembly accordingto a further aspect of the invention, having disposed therein amultiplicity of rectangular parallelepiped fluid storage and dispensingvessels according to the invention.

DETAILED DESCRIPTION OF THE INVENTION, AND PREFERRED EMBODIMENTS THEREOF

The present invention is based on the discovery that a physicaladsorbent-based fluid storage and dispensing apparatus may be fabricatedutilizing a fluid storage and dispensing vessel having a rectangularparallelepiped conformation, with surprising and unexpected advantagesas regards the nature and extent of the desorption process, the packingdensity achievable for the physical sorbent medium in the vessel, andthe utility of the fluid storage and dispensing apparatus comprisingsuch vessel for semiconductor manufacturing operations.

By way of background to the ensuing explanation of the unanticipatedadvantages of the rectangular parallelepiped conformation vessel in thefluid storage and dispensing apparatus of the present invention, itwould on initial consideration appear to be highly disadvantageous toemploy a rectangular parallelepiped conformation for aphysical-adsorbent-based fluid storage and dispensing system, since: (i)a rectangular parallelepiped vessel has six faces, and twelve weld-linesrequired for fabrication if each face of the vessel is a separate piece(by contrast, a cylindrical vessel may be formed without seams fromtubular rolled steel stock); (ii) consistent with (i), the fabricationcost of a rectangular conformation vessel would be expected to besubstantially higher than for a corresponding cylindrical vessel; (iii)a rectangular parallelepiped conformation involves “sharp” corners atthe juncture of adjacent perpendicularly oriented walls that offer thepotential of forming voids at the line of juncture, wherein the sorbentbed would not “pack” against the corner, relative to a correspondingcylindrical geometry vessel (which is free of such corners, and insteadis a minimum cross-sectional area shape circumscribing the bed ofphysical sorbent material in the interior volume of the vessel); and(iv) the intersection of two perpendicular walls with one anotherproduces a joint that is susceptible to rupture by pressure or forcedirected thereon, relative to a “seamless” cylindrical vessel.

Applicant has discovered, however, that the rectangular parallelepipedconformation results in a vessel which does have less tightly packedsorbent bed regions adjacent the seams at the intersection of adjacentwalls, but that rather than being a disadvantage, such lower densitysorbent bed regions are in fact advantageous as higher gas flowconductance pathways for interstitial desorbed or unadsorbed gas to flowout of the bulk volume of the sorbent bed.

Further, precisely because the cylindrical vessel is a minimumcross-sectional area conformation, with a minimum circumferential extentof circumscribing wall area, the amount of sorbent that is “presented”to the wall in the cylindrical vessel is maximized. Considering theconverse, the peripheral extent of the wall that bounds (is adjacent to)the sorbent bed in cross-section is much greater in the rectangularparallelepiped conformation than in the cylindrical vessel. Therectangular parallelepiped conformation thereby enables higher volumeegress of gas from the vessel than from a correspondingly sizedcylindrical vessel, because the wall surface bounding the sorbent bed isnon-adsorbing in character, and there is proportionally more of it inthe rectangular conformation vessel, at the outer margins of the sorbentbed, than there is in the cylindrical vessel. As a result, the desorbedgas at the wall regions is less readsorbed subsequent to its initialdesorptive release from the sorbent medium than desorbed gas in theinterior portions of the sorbent bed.

Further, the rectangular parallelepiped conformation has particularutility for holding sorbent in a monolithic form, of a type as disclosedfor example in U.S. Pat. No. 6,743,278 issued Jun. 1, 2004 to J. D.Carruthers for “Gas Storage and Dispensing System with Monolithic CarbonAdsorbent.” As used in such context, “monolithic” means that the sorbentmedium is in a unitary or block-like form, in contradistinction toconventional finely divided forms such as beads, particles, granules,pellets, and the like, which are generally utilized in the form of a bedcomprising a multiplicity of such beads, particles, granules, pellets,etc. Thus, in the bed form of multiple finely divided physical adsorbentelements, the void volume of the active sorbent is in major partinterstitial, or inter-particle, in character, varying according to thedimensions, shape and packing density of the sorbent particles. Bycontrast, in a monolithic form, the void volume of the active sorbent isin form of porosity intrinsic to the sorbent material and voids that mayhave been formed in the bulk sorbent body during its processing.

In one embodiment, the invention relates to a rectangular parallelepipedvessel defining a closed interior volume and having a port to which iscoupled a gas dispensing assembly, for selective discharge of gas fromthe vessel. The rectangular parallelepiped vessel contains sorbentmedium in a suitable form, e.g., in a form that provides sufficientcapacity for sorptive retention of gas in a desired quantity, thatprovides good desorptive release of gas under desorption conditions,that provides good working capacity with good heels behavior (i.e., highextent of desorption of initially adsorbed gas), and that has anappropriate sorptive affinity for the gas of interest so that low gaspressure is maintained in the interior volume of the vessel duringstorage of gas therein.

The physical adsorbent can therefore be in a divided form, e.g., in theform of beads, pellets, rings, platelets, tablets, cylindricalextrudates, granules, cubic shapes, molded geometrically regular orirregular shapes, or any other form that is usefully applied to theadsorbent medium when disposed in the interior volume of the rectangularparallelepiped vessel and utilized therein for holding the gas to bestored in and selectively dispensed from such vessel.

The physical adsorbent when provided in such divided form is utilized inthe form of a mass of such forms, as a bed of sorbent medium. The sizeof such divided forms may be readily determined for a given end useapplication of the invention, based on mass transfer considerations andpacking factors for the particular shaped divided form that is employedin the vessel.

Alternatively, the physical adsorbent may be in a monolithic form,comprising blocks, bricks, boules or similar forms of the adsorbentmaterial that are of a size commensurate with the rectangularparallelepiped vessel, so that vessel contains one or a small number,e.g., less than 75, more preferably less than 20, of the discretemonolithic articles. In a further preferred aspect, the vessel containsno more than 8 such discrete monolithic articles, even more preferablyno more than four such articles, and most preferably the vessel containsa single monolithic physical adsorbent article.

The monolithic article(s) deployed in the rectangular parallelepipedvessel provide(s) a sorbent mass (aggregately, if the sorbent isprovided in the form of multiple monolithic articles) that is preferablyconformed in size and shape to the interior volume of the rectangularparallelepiped vessel, so that the sorbent mass of the monolithicarticle(s) occupies at least 60% of the interior volume of therectangular parallelepiped vessel, preferably in a range of from about75% to about 95% of the interior volume of such vessel.

If provided in a single monolithic form, the sorbent medium may for suchpurpose be formed in situ in the vessel, e.g., by pyrolysis of anorganic resin that is in liquid or otherwise flowable form, with whichthe vessel is filled prior to pyrolysis of same in the vessel.

If alternatively provided in the form of multiple monolithic articles,each of such articles has a length that is between 0.3 and 1.0 times theheight of the interior volume of the vessel, and a cross-sectional areathat is between 0.1 and 0.5 times the rectangular cross-sectional areaof the vessel. Each monolithic member preferably has a rectangularparallelepiped shape for maximizing the volumetric usage of the interiorvolume of the vessel, wherein each of the monolithic members may belaterally and/or longitudinally abutted in surface contact with adjacentmonolithic members in the interior volume of the vessel. Alternatively,in some instances, it may be desirable for the sorbent monolithicmembers to be in the form of solid cylinders, with the respectivecylindrical members being loaded into the interior volume so as totangently abut one another along their facing side surface, and to atleast partially abut one another in face-to-face contact at theircircular cross-section end surfaces.

The rectangular parallelepiped shape of the gas storage and dispensingvessel in the gas storage and dispensing apparatus of the presentinvention accommodates the vessel to installation and containment in agas cabinet, such as is widely used in semiconductor manufacturingfacilities, with minimization of wasted volume inside the gas cabinet.This achieves a substantial benefit in relation to conventionalcylindrical vessels, which by virtue of their circular cross-sectioncreate wasted volume in proximity to the walls and other rectangular andsquare components of the gas cabinet that are adjacent or in closeproximity to the gas storage and dispensing vessel.

Further, when multiple vessels are deployed in the gas cabinet, and arearranged in side-by-side fashion, the circular cross-section ofconventional cylindrical vessels produces a significant wasted volume inthe interior of the gas cabinet, whereas rectangular parallelepipedvessels of the present invention can be arranged in side-by-siderelationship with their adjacent side wall surfaces in abutting contactwith each other or in near proximity, to minimize the presence andamount of the wasted space in the interior of the gas cabinet.

The rectangular parallelpiped vessels in the gas storage and dispensingapparatus of the invention therefore achieve significant reduction ofunused space within the gas cabinet, relative to conventionalcylindrical vessels. As a result, more gas can be stored in sameinterior volume of the gas cabinet with the vessels of the inventionthan is possible with the cylindrical vessels of the prior art. This inturn reduces the frequency of the vessel change-outs in operation of thegas cabinet, which further reduces the operational time that is consumedin changing out depleted gas supply vessels, and further reduces thecost of ownership of the gas cabinet facility. The rectangularparallelpiped vessel of FIG. 1 accommodates a volume-fill space of 3.62liters whereas a conventional cylindrical vessel taking the samephysical location in the gas box has a volume-fill space of only 2.2liters. In addition, the gas cabinet for a same inventory of suppliedgas can be made smaller, thereby reducing the footprint of the gascabinet and the airflow required to produce the ventilation necessaryfor safety in the gas cabinet.

As used herein, the term “gas cabinet” and “gas cabinetry” refer toenclosures in which is deployed at least one gas supply vessel. Theenclosure may be equipped with flow circuitry, including piping,manifolding, valving, mass flow controllers, pressure and temperaturemonitoring devices, and the enclosure may be ventilated, involving flowof clean dry air (CDA) therethrough from a source of same exterior tothe enclosure, with the vented exhaust being discharged to a houseexhaust treatment system for the facility in which the enclosure isdeployed, or otherwise treated and recirculated through the enclosure asa recycled sweep gas.

The enclosure in specific applications may be a component part of asemiconductor process tool, such as a gas box in an ion implantationsystem.

The enclosure can be arranged for holding a single gas supply vessel, orit may be arranged for holding an array of vessels, e.g., 2 or 3 or morevessels, wherein each may be deployed to provide a same or differentgas, and wherein the vessel(s) may be coupled with flow circuitry in anysuitable manner, e.g., with a back-up vessel in the enclosure to whichthe flow circuitry is switched upon depletion of the gas from acurrently on-stream vessel, by suitable monitoring and controlcomponentry in the enclosure, such as a cycle timer joined to amicroprocessor controller and arranged to operate the on-stream vesselfor a predetermined time, or a time during which one or more monitoredprocess conditions is in a predetermined set point range.

The rectangular parallelepiped vessel in the gas supply apparatus of theinvention can be fabricated in any suitable manner, e.g., by welding ofsheet metal or by extrudation of thin sheet metal stock. The metal maybe of any suitable type, including steel, stainless steel, aluminum,copper, brass, bronze, or other metals or metal alloys. Alternatively,the vessel may be formed by similar techniques or other techniques,e.g., ultrasonic bonding, melt bonding, laser welding, etc., frompolymeric materials, ceramic materials, glasses and vitreous materials,and composite materials having suitable character as a material ofconstruction for the gas storage and dispensing vessel, e.g., withsufficiently low permeability for the gas containment function of thevessel.

The vessel is suitably fabricated with a port at a face thereof, e.g.,at a top face of the vessel, to which the valve head or other dispensingassembly can be joined in leak-tight fashion, e.g., by suitable bondingor sealing techniques and materials appropriate to the specific materialof the vessel and the dispensing means. The vessel may be charged withthe particulate sorbent through the open port prior to joining of thevalve head to the vessel, or the vessel may be formed with installationof the monolithic form of the sorbent prior to attachment of the finalwall member, or the monolithic sorbent can be formed in situ aspreviously described.

Once installed in the vessel, the sorbent medium may be degassed, orpretreated in other manner, such as by thermal treatment,pressurization/depressurization cycling, or other method. The sorbategas is charged to the vessel prior to final sealing, and the vesselduring such charging may be cooled or otherwise thermally managed, suchas by step-wise charging, to dissipate the heat of sorption.

The charged vessel then is sealed, e.g., by closure of the head valve,and thereafter the charged gas supply vessel can be stored, transported,or placed in use, as appropriate.

Referring now to the drawings, FIG. 1 is a perspective view of arectangular parallelepiped fluid storage and dispensing vessel 10according to one embodiment of the present invention, with a pipe valveconnection valve head 12 and handles 14 welded to the top face of thevessel. The vessel 10 in a specific embodiment is formed with a weldedsteel wall construction, having a square cross-section along thevertical (longitudinal) axis of the vessel. The walls of the vessel are0.100 inch thick carbon steel, and the interior volume of the vessel is3.62 liters. The handles 14 are ¼ inch rod stock, formed into the shapeshown, and welded at the respective ends to the vessel 10.

The dispensing valve of the pipe valve connection valve head 12 isthreadably engaged with the vessel 10, by a 1½″ pipe thread connection.The valve head may have any suitable number of ports, e.g., single portvalve heads, dual port valve heads, 3-port valve heads, etc.

FIG. 2 is a perspective view of a rectangular parallelepiped fluidstorage and dispensing vessel 10 according to another embodiment of thepresent invention, with a flange type valve connection valve head 12Aand handles 14 welded to the top face of the vessel 10. The valve headof FIG. 2 therefore differs from that shown in FIG. 1, as having aflange type connection in the FIG. 2 embodiment, as opposed to the pipetype connection shown in FIG. 1. The flange connection shown in FIG. 2comprises a flange member with an o-ring groove that bolts to the topsurface of the vessel 10.

The gas storage and dispensing vessels in the embodiments of FIGS. 1 and2 have interior volumes that contain physical adsorbent mediumsorptively retaining a sorbate gas thereon, with the sorbate gas beingdispensed through the valve head through dispensing flow circuitry whensuch circuitry is coupled with the valve head and the valve in the valvehead is opened to permit desorption of the sorbate gas and discharge ofthe desorbate gas from the vessel to the flow circuitry and downstreamgas-consuming process. The sorbate gas may be desorbed from the sorbentmaterial for discharge from the vessel in any suitable manner, involvingfor example pressure-mediated desorption, thermally-mediated desorption,and/or concentration gradient-mediated desorption.

The downstream gas-consuming process may be of any suitable type, e.g.,a semiconductor manufacturing process. Illustrative examples of suchsemiconductor manufacturing processes include, without limitation, ionimplantation, doping by methods other than ion implant, chemical vapordeposition, reactive ion etching, photoresist residue removal, etc.

The sorbate gas likewise can be of any suitable type, including by wayof example, without limitation, arsine, phosphine, nitrogen trifluoride,boron trifluoride, boron trichloride, diborane, trimethylsilane,tetramethylsilane, disilane, silane, germane, organometallic gaseousreagents, hydrogen selenide, hydrogen telluride, and the like. Thesorbate gas may be widely varied in type, depending on the physicaladsorbent medium employed and the end use application for which thedesorbed and dispensed gas is to be employed.

The sorbate gas can be contained in the vessel at any suitable pressure,including subatmospheric, atmospheric and superatmospheric pressures.The pressure of the stored fluid may be subatmospheric, e.g., asubatmospheric pressure that does not exceed about 700 torr for dopingand ion implantation applications of the invention. For example, ionimplantation gases, e.g., arsine, phosphine, and boron trifluoride, maybe stored in the vessel at a pressure in a range of from about 400 toabout 700 torr. Gas may also be stored in the vessel at substantiallyatmospheric pressure, or at low superatmospheric pressure, e.g., apressure not exceeding about 1500 torr, in various specific applicationsof the invention.

FIGS. 3A-3B provide front elevation views of a rectangularparallelepiped fluid storage and dispensing vessel of the type shown inFIG. 2, showing details of the structure thereof. FIG. 3A shows avessel, without a lid, including at least one wall 17 bounding aninterior volume containing adsorbent material 16. FIG. 3B shows thevessel of FIG. 3A, with the vessel being closed with a lid having anassociated valve assembly 14. As illustrated, the gas storage anddispensing vessel contains an interior volume in which the physicaladsorbent 16 is disposed. The physical adsorbent may be of any suitabletype, including carbon, activated carbon, metal-impregnated carbon,molecular sieve (aluminosilicate) materials, porous silicon, silica,alumina, styrene divinylbenzene polymeric materials, sorptive clays,functionalized sintered glass media, etc. As shown in FIGS. 3A-3B, thephysical adsorbent 16 includes a cavity 19 in which a downwardlyextending portion 14A of the valve 14 may be received.

The physical adsorbent may likewise be of any suitable form appropriateto the use of the gas storage and dispensing system in the particularapplication for which it is employed. The sorbent medium may be in adivided form, such as beads, granules, pellets, etc., or it may be in amonolithic form as hereinabove described.

The vessel is equipped with a flange type valve connection valve head12A, with the flange member being secured to the top wall of the vesselin a leak-tight manner by means of O-ring seal 18, and the handles beingsecured by welding to the top wall of the vessel.

In another variation of the structure of the parallelepiped-shapedstorage and dispensing vessel, FIG. 3 shows the vessel as being providedwith an optional cap 13. The cap 13, depicted in schematic form, islikewise of rectangular parallelepiped shape, and is provided withopenings 15 on respective side faces of the cap. The vessel whenprovided with such cap can be fabricated without the handle shown inFIG. 3, or alternatively, a handle can be fabricated on the cap 13. Theopenings 15 on the cap 13 provide a handle structure, allowing theentire vessel assembly to be manually gripped and transported, and suchopenings also permit access to the valve head 12A, e.g., for coupling ofa dispensing line to the discharge port of the valve head.

The cap 13 can be secured to the vessel container body in the modifiedvessel construction of FIG. 3, in any suitable manner, as for example bymeans of complementarily mating coupling elements on the vesselcontainer body and the cap, whereby the cap and vessel container bodycan be mechanically interlocked with one another, e.g., a bayonet-typecoupling, threadably engageable matable coupling, mechanical fastenercoupling (latch-type coupling, bolt-and-nut type coupling, etc.),spring-biased compression fit coupling, etc.

The cap also affords the advantage of protecting the valve head fromimpact, compression/tension forces in contact with other structures orbodies, and other interactions with other objects holding the potentialfor damaging the valve head or impairing its utility.

The cap can be further provided with a handle element, welded orotherwise joined to the cap 13, e.g., to a side surface thereof oraffixed in other manner to the cap.

As a still further alternative, the vessel assembly can include separatecap and handle members, each separately coupled to the vessel containerbody.

As a specific example of a fluid storage and dispensing apparatus inaccordance with the present invention, an apparatus of the type shown inand described with reference to FIG. 3 is fabricated with a vesselhaving a 4.5 inch×4.5 inch cross-section. The height of the vessel is12.3 inches, and the wall and floor of the vessel are 0.188 inchthickness. The vessel is formed of welded box tubing. The vessel can befabricated with a flanged, O-ring seal top plate, or alternatively witha welded top plate.

The flanged, O-ring seal top plate arrangement can be effected with atop plate of suitable thickness, e.g., about 0.61 inch, having a centralopening. An O-ring, e.g., of Viton® elastomer, is positioned around theperiphery of the central opening, and a valve insertion ring is thenfixed in position in the opening. The valve insertion ring includes anupper disc portion from which downwardly depends a plug portion ofsmaller diameter than the upper disc portion, the plug portion fittingclosely within the central opening of the top plate, with the O-ringbetween the underside of the upper disc portion and the upper surface ofthe top plate.

The vessel cap has a twist and lock mechanism, with a spring plungerlocking key including elongated slots in the cap base, and threeshoulder bolts. In use, the cap base elongated slots are pressed downover the three shoulder bolts, rotated 15 degrees to engage the bolts,and the locking plunger thereafter prevents further rotation andpositionally fixes the cap on the vessel. Alternatively, the vessel caphas a direct attachment and two locking plungers.

The cap side wall openings (openings 15 in FIG. 3) are 3 inch×3 inchopenings, and plastic grip-pads can be affixed to the upper edges of theopenings, to facilitate grippability for manual handling of theapparatus.

The vessel of the illustrative apparatus can be drawn over mandrel (DOM)square-cross-sectioned tubing, and can have rounded corners or sharp 90°corners, with the square-cross-sectioned tubing being formed from awelded tube stock, with a weld that disappears in the cold drawingprocess. The result of such cold drawing process is a seamlesssquare-cross-sectioned tube closed at one end and open at its oppositeend. The top plate is welded to the open end of the drawnsquare-cross-sectioned tube after insertion of the monolithic adsorbentinto the interior volume of the square-cross-sectioned tube. The topplate can have an NPT thread to accommodate the valve head assembly, andshoulder pins to accommodate the cap when the cap is of a bayonet capdesign.

The vessel in the illustrative apparatus can be formed of forgedaluminum, steel, or other suitable material of construction. The topplate can be formed of a same or different material of construction.

As discussed hereinabove, fluid storage and dispensing apparatus inaccordance with the present invention are usefully disposed in gascabinets in a manner affording substantially improvement over thecylindrical vessels conventionally used in the prior art. By virtue oftheir rectangular parallelepiped shape, vessels of the present inventioncan be deployed in a gas cabinet in a conformal manner, as regards therectangular geometry of conventional gas cabinetry. By shapeconformality to the gas cabinet (i.e., with walls of the fluid storageand dispensing vessel in close facing proximity or even, as ispreferred, in abutting relationship to a side wall of the gas cabinet),the “lost volume” attributable to cylindrical vessels is avoided in thepractice of the invention.

FIG. 4 is a schematic representation of a gas cabinet assembly accordingto a further aspect of the invention, comprising a gas cabinet 20 havingan interior volume 30, in which is disposed rectangular parallelepipedgas storage and dispensing vessels 50 and 52 as components of respectivegas storage and dispensing apparatus constructed according to theinvention.

The gas storage and dispensing apparatus including gas storage anddispensing vessel 50 has a valve head 48 coupled with automatic valveactuator 44, and operable to open the valve in valve head 48 to flowdesorbed sorbate gas from vessel 50 into branch discharge line 34connected to manifold line 24.

The automatic valve actuator 44 is connected by signal transmission line46 to central process unit (CPU) 58, which may comprise a generalpurpose programmable computer programmably arranged to carry outoperation with dispensing of gas from the vessel 50 during apredetermined period of operation of the gas cabinet system, byactuation of the automatic valve actuator 44 for such purpose, andshut-off of the gas flow control valve in valve head 48 by appropriatesignal transmitted in line 46 to automatic valve actuator 44.

Thus, gas dispensed from vessel 50 flows through the valve head 48 anddischarge line 34 to manifold line 24 coupled with gas flow dispensingregulator 36 and finally is discharged in the outlet line 38 coupled tothe gas flow dispensing regulator 36. The gas flow dispensing regulator36 is coupled by signal transmission line 60 to the CPU 58, formodulation of the gas flow dispensing regulator 36 in accordance withthe gas demand of the downstream gas-consuming process (not illustratedin FIG. 4).

The FIG. 4 gas cabinet assembly also includes the correspondinglyarranged gas storage and dispensing vessel 52, equipped with valve head54 and automatic valve actuator 56 coupled to CPU 58 by signaltransmission line 66, whereby gas from vessel 52 may be selectivelyflowed in the branch discharge line 22 to manifold line 24 coupled withgas flow dispensing regulator 36 in the same manner as thefirst-described gas storage and dispensing apparatus comprising vessel50.

In the FIG. 4 gas cabinet assembly, the gas storage and dispensingvessels 50 and 52 are arranged in side-by-side abutting relationship toone another, with vessel 50 being abuttingly reposed against the sidewall of the gas cabinet 20, and both vessels 50 and 52 being abuttinglyreposed against a back wall of the gas cabinet 20.

In the use of the physical adsorbent-based gas storage and dispensingsystems of the invention, the gas cabinet assembly can be materiallysimplified by eliminating the ducting typically employed for flowing thevent gas from the gas cabinet to the exhaust system of the semiconductormanufacturing facility, which typically includes a large scrubber fortreating the exhaust streams of the facility. Because the physicaladsorbent-based gas storage and dispensing system of the invention is alow pressure gas supply system, the potential egress rate of gas fromdamaged or malfunctioning valve heads, couplings, etc. in the gascabinet is minimized, and the rate of flow of sweep gas such as CDAthrough the cabinet interior volume can be markedly reduced in relationto gas cabinet systems employing high pressure gas cylinders of theprior art.

In another aspect of the invention, the enhanced safety of the physicaladsorbent-based gas storage and dispensing systems can be exploited toeliminate the piping to the exhaust scrubber system, and to utilize inplace thereof a simple point-of-use scrubber in the gas cabinet itself,to ensure the removal of any low level contaminants in the vent gasdischarged from the gas cabinet.

An illustrative embodiment of such point-of-use scrubber isschematically shown in the FIG. 4 gas cabinet system. As illustrated, aninlet line 25 delivers CDA or other sweep gas into the gas cabinet 20,to purge out the interior volume 30 of the cabinet so that any toxic orhazardous contaminants in the cabinet are displaced from the interiorvolume and do not accumulate to any levels that approach the thresholdlimit value (TLV) of the specific hazardous components that may beinvolved in the gas dispensing operation involving the gas sourcevessels in the cabinet.

The cabinet is equipped in the interior volume 30 of the cabinet 20 witha point-of-use gas scrubber 61 which takes in the vent gas from theinterior volume 30 and subjects it to contact with a suitable scrubbermedium, e.g., a chemisorbent reactive with the gas contaminant speciesto remove same to below detectable and hazardous concentrations. The gasscrubber 61 may as shown be wall-mounted on a side wall of the cabinet.Gas contacted with the scrubber medium is discharged from the cabinet 20in vent gas discharge line 63.

Although shown schematically for ease of illustration and description,it will be recognized that the scrubber may be deployed in any suitablemanner, e.g., as a small scrubber unit on the inlet (low pressure side)of a venturi device in a gas panel in the gas cabinet. The gas in ventgas discharge line 63 may be passed to the ducting of the house exhaust,bypassing the house exhaust scrubber and thereby reducing the gas burdenon the house scrubber, while maintaining a high level of safety asregards the character of the gas discharged from the gas cabinet.

In the point-of-use scrubber employed in the embodiment of FIG. 4, thescrubber may be equipped with an end-point detector, to ascertain theend point of the scrubber material (viz., its approach to exhaustion asa result of reactive depletion of the scrubber material in extended usein the gas cabinet). Various types of endpoint detection can beemployed.

In a first type of endpoint detector, a sight glass may be incorporatedin the scrubber, e.g., by installation thereof in a window opening ofthe scrubber housing or container, when the scrubber is of a type thatchanges color when it contacts the target contaminant species in the gascabinet vent gas.

The incipient exhaustion of the scrubber medium can thereby be visuallymonitored by an operator of the gas cabinet, and the change-out of thescrubber medium, to replace the depleted material with fresh scrubbermedium, can be efficiently scheduled as part of a program of routineinspection of the scrubber medium through the sight glass.

A second type of endpoint detector uses a colorimetric sensor toautomatically detect the color change of the scrubber medium and toactuate an alarm or report to alert operational personnel of the need tochange out the scrubber. The sensor may also be arranged to shut off theflow valves in the gas cabinet to prevent operation from resuming untilthe scrubber medium is changed out.

A toxic gas monitor (TGM) may also be integrated into the body of thescrubber unit in a third approach to endpoint determination. Thisapproach is usefully employed where the scrubber medium employed in thepoint-of-use scrubber unit does not evidence a color change in contactwith the target gas contaminant species.

A fourth endpoint determination technique utilizes a programmable logiccontroller (PLC) unit to count the number of change-outs of gas storageand dispensing vessels since the installation of the scrubber unit, andto actuate alarm or report means to provide an output indicative of theneed to change out the scrubber unit. The PLC unit may be arranged tocalculate the amount of gas to which the scrubber will be exposed from asingle gas storage and dispensing vessel and from the inputted scrubbermedium capacity, the number of gas storage and dispensing vesselchange-outs that can be performed before the scrubber medium isexhausted, is determined.

It will be appreciated that the compositions and methods of theinvention may be practiced in a widely variant manner, consistent withthe broad disclosure herein. Accordingly, while the invention has beendescribed herein with reference to specific features, aspects, andembodiments, it will be recognized that the invention is not thuslimited, but is susceptible of implementation in other variations,modifications and embodiments. Accordingly, the invention is intended tobe broadly construed to encompass all such other variations,modifications and embodiments, as being within the scope of theinvention hereinafter claimed.

What is claimed is:
 1. A method of reducing flow of sweep gas through an interior volume of a ventilated gas cabinet arranged to contain a gas supply system including gas supply vessel(s), said method comprising using physical adsorbent-based gas storage and dispensing vessel(s) as said gas supply vessel(s), and reducing flow of sweep gas through said interior volume, in relation to flow of sweep gas through said interior volume when the gas cabinet contains gas supply vessel(s) that are not physical adsorbent-based, wherein the physical adsorbent-based gas storage and dispensing vessel(s) comprise a valve head coupled with an automatic valve actuator, wherein the automatic valve actuator is operable to open a valve in the valve head to dispense gas from the gas supply vessel(s), and wherein the physical adsorbent comprises a multiplicity of monolithic carbon adsorbent articles of cylindrical form, abutting one another in face-to-face contact at circular cross-section end surfaces thereof.
 2. The method of claim 1, wherein the gas supply vessel(s) contain a sorbate gas comprising a semiconductor manufacturing gas.
 3. The method of claim 2, wherein the semiconductor manufacturing gas is selected from the group consisting of gases for ion implantation, gases for non-ion implant doping, gases for chemical vapor deposition, gases for reactive ion etching, and gases for photoresist residue removal.
 4. The method of claim 1, wherein said gas supply vessel(s) contain a sorbate gas selected from the group consisting of arsine, phosphine, hydrogen selenide, hydrogen telluride, nitrogen trifluoride, boron trifluoride, boron trichloride, diborane, trimethylsilane, tetramethylsilane, disilane, silane, germane, and organometallic gaseous reagents.
 5. The method of claim 1, wherein the gas supply vessel(s) contain a sorbate gas at subatmospheric pressure.
 6. The method of claim 1, wherein the gas supply vessel(s) contain a sorbate gas at pressure not exceeding 1500 torr.
 7. The method of claim 1, wherein the sweep gas discharged from the interior volume of the ventilated gas cabinet is discharged to a house exhaust system of a facility in which the ventilated gas cabinet is deployed.
 8. The method of claim 1, wherein the sweep gas is discharged from the interior volume of the ventilated gas cabinet for treatment and is recirculated through the interior volume of the ventilated gas cabinet as a recycled sweep gas.
 9. The method of claim 1, wherein the sweep gas comprises clean dry air.
 10. The method of claim 1, wherein the automatic valve actuator is operatively connected to a central process unit comprising a programmable computer programmably arranged to carry out operation with dispensing of gas from the gas supply vessel(s) during a predetermined period of operation of the ventilated gas cabinet, by actuating the automatic valve actuator for such operation, and terminating the dispensing at the conclusion of the predetermined period of operation.
 11. A gas cabinet assembly comprising an enclosure with an interior volume that contains physical adsorbent-based gas supply vessel(s), and arranged to be ventilated by flow of sweep gas through the interior volume from a source of said sweep gas exterior to the enclosure, and discharge thereof from the enclosure, wherein the gas cabinet assembly is arranged so that it flows said sweep gas through the enclosure at a reduced rate of flow in relation to a corresponding gas cabinet assembly containing gas supply vessel(s) lacking said physical adsorbent, wherein the physical adsorbent-based gas storage and dispensing vessel(s) comprise a valve head coupled with an automatic valve actuator, wherein the automatic valve actuator is operable to open a valve in the valve head to dispense gas from the gas supply vessel(s), and wherein the physical adsorbent comprises a multiplicity of monolithic carbon adsorbent articles of cylindrical form, abutting one another in face-to-face contact at circular cross-section end surfaces thereof.
 12. The gas cabinet assembly of claim 11, wherein the enclosure is a component part of a semiconductor process tool.
 13. The gas cabinet assembly of claim 11, wherein the enclosure comprises a gas box in an ion implantation system.
 14. The gas cabinet assembly of claim 11, wherein the gas supply vessel(s) contain a sorbate gas comprising a semiconductor manufacturing gas.
 15. The gas cabinet assembly of claim 14, wherein the semiconductor manufacturing gas is selected from the group consisting of gases for ion implantation, gases for non-ion implant doping, gases for chemical vapor deposition, gases for reactive ion etching, and gases for photoresist residue removal.
 16. The gas cabinet assembly of claim 11, wherein said gas supply vessel(s) contain a sorbate gas selected from the group consisting of arsine, phosphine, hydrogen selenide, hydrogen telluride, nitrogen trifluoride, boron trifluoride, boron trichloride, diborane, trimethylsilane, tetramethylsilane, disilane, silane, germane, and organometallic gaseous reagents.
 17. The gas cabinet assembly of claim 11, wherein the gas supply vessel(s) contain a sorbate gas at subatmospheric pressure.
 18. The gas cabinet assembly of claim 11, wherein the gas supply vessel(s) contain a sorbate gas at pressure not exceeding 1500 torr.
 19. The gas cabinet assembly of claim 11, wherein the sweep gas discharged from the enclosure is discharged to a house exhaust system of a facility in which the enclosure is deployed, or treated and recirculated through the enclosure as a recycled sweep gas.
 20. The gas cabinet assembly of claim 11, wherein the automatic valve actuator is operatively connected to a central process unit comprising a programmable computer programmably arranged to carry out operation with dispensing of gas from the gas supply vessel(s) during a predetermined period of operation of the gas cabinet assembly, by actuating the automatic valve actuator for such operation, and terminating the dispensing at the conclusion of the predetermined period of operation. 